Member2.

NULL

does soapstone retain heat like they say it does? and if so, can you buy a slab or bricks to place on top of a stove to help distribute heat? i've heard good things but wanted to ask first before i jump into anything.

as a side note, my firewood guy brought me more wood today. got a full cord and half of it was hedge apple. he's got 4 more cords just like it. gonna be a warm winter. woo hoo!

randall

englander add-on furnace
aurora wood burner in the garage
buck insert in the living room
US military camping stove
max the super beagle

Member2.

NULL

i figure once the fire died down, like in the morning, the stone would still throw off some heat. i know it wouldn't be much. my one wood stove sits on a 10 foot by 10 foot pad of bricks. basically, the brick layer laid the entire floor with bricks and the wall is floor to ceiling also. that part of the house stays warm well into the morning with almost no fire going. the bricks soak up the heat, all 1200 of them. i wanted to see if i could do something close to that with the stove in the front of the house.

i'll have 5 or 6 full cords on hand this year. hopefully that will do it.

randall

englander add-on furnace
aurora wood burner in the garage
buck insert in the living room
US military camping stove
max the super beagle

Minister of Fire2.

NULL

There are two factors that dominate the capacitive effect of a wood stove: mass & emissivity. Mass is typically the dominant factor, and soapstone stoves being slightly heavier than cast iron stoves, are slightly better in this regard. Emissivity of a matte stone surface will also be lower than a glossy cast iron enamel, further slowing radiation... Again, slightly.

There is a penalty to pay, though. The same time constant that helps the stove radiate and cool more slowly, also makes it heat up more slowly.

There are some who call me...mod.2.

NULL

Staff Member

Also, by laying it on top of the stove, it may not have a very good heat transfer from the steel of the stove. If that's the case, you'll overheat the stove as the soapstone will actually work to insulate your stove. Of those who have tried this in the past, I can't recall one that had success and continues to do it.

If anything, I'd say replace your firebricks with soapstone.

pen

- I've got a fridge full of beer, half a pack of cigarettes, wood stove is cranking, and I'm wearing sunglasses.
- Using an Englander-30 to burn wood and forearms.

Member2.

NULL

yep, it's a ton bricks. literally. i don't own too much furniture. i have a small folding table i put up with a chair if i want to sit down and eat but i mostly put my wood there because it's easy to clean up. this was the dining room when i bought the house. i don't really dine and it's just me and the dog so now it's the wood stove room. i'm revamping the whole house so this room will be done in all knotty pine. it will look great when i'm done.

randall

englander add-on furnace
aurora wood burner in the garage
buck insert in the living room
US military camping stove
max the super beagle

Minister of Fire2.

NULL

There are two factors that dominate the capacitive effect of a wood stove: mass & emissivity. Mass is typically the dominant factor, and soapstone stoves being slightly heavier than cast iron stoves, are slightly better in this regard. Emissivity of a matte stone surface will also be lower than a glossy cast iron enamel, further slowing radiation... Again, slightly.

There is a penalty to pay, though. The same time constant that helps the stove radiate and cool more slowly, also makes it heat up more slowly.

Click to expand...

A bit of a hint here. Do not pay much attention to the saying that the soapstone takes a long time to heat up. It does not. Yes, it will take longer than steel but it is not a long time at all.

Minister of Fire2.

NULL

does soapstone retain heat like they say it does? and if so, can you buy a slab or bricks to place on top of a stove to help distribute heat? i've heard good things but wanted to ask first before i jump into anything.

as a side note, my firewood guy brought me more wood today. got a full cord and half of it was hedge apple. he's got 4 more cords just like it. gonna be a warm winter. woo hoo!

Click to expand...

There have been some try this and as a young lad we used to have an old soapstone that we'd heat on the wood stove for use in the car or sometimes to warm up the bed. Those were cold times with those old stoves and homes with no insulation.

We know one with a soapstone stove who tried adding another stone to try this and it did not work well at all. Some have tried on steel and cast too but not really good. However, we have small soapstone blocks that we keep on the stove top and use for boot driers and glove driers and even just to keep an extra pair of gloves warm when cutting wood in winter. We also use them under the pots and pans the wife uses for cooking.

On that hedge apple, I hope it is not freshly cut or freshly split. Wood won't dry worth a hoot until it has been split and stacked out in the open air. The most common problem, especially with the epa stoves is poor fuel. The old thing about cutting the winter's wood in the fall is a dead idea. It just don't work.

Minister of Fire2.

NULL

i figure once the fire died down, like in the morning, the stone would still throw off some heat. i know it wouldn't be much. my one wood stove sits on a 10 foot by 10 foot pad of bricks. basically, the brick layer laid the entire floor with bricks and the wall is floor to ceiling also. that part of the house stays warm well into the morning with almost no fire going. the bricks soak up the heat, all 1200 of them. i wanted to see if i could do something close to that with the stove in the front of the house.

i'll have 5 or 6 full cords on hand this year. hopefully that will do it.

Click to expand...

That is quite the room - I saw the picture too. Now, if you did that with soapstone it would be impressive as well (not to mention MUCH more expensive). Basically you have built up a very good thermal mass there. If it is an interior room then you are storing it very well and it will release into the house over time.

There are folks who have done the math on how much heat can be stored in a slab of stone on the stove and frankly it isn't much in the scheme of things. 2000lbs of stone in the room is quite another matter though!

Woodstock Progress Hybrid (2012) - Just getting warmed up...
Woodstock Fireview (2009) - Sold to a good friend
New to wood burning fall 2008, learning as fast as I can to recognize my mistakes earlier and earlier...

I let the coals burn until the stove temp drops down to about 280 before I reload it. Since the stone is still putting off a lot of heat I get several hours of heat back at the end of the burn cycle. By using this method I only have to load it 3 times a day while burning 24-7 maybe 4 if it is really cold out.

Minister of Fire2.

NULL

I let the coals burn until the stove temp drops down to about 280 before I reload it. Since the stone is still putting off a lot of heat I get several hours of heat back at the end of the burn cycle. By using this method I only have to load it 3 times a day while burning 24-7 maybe 4 if it is really cold out.

Click to expand...

That is more of an indication that your stove is a little over-sized for your needs, which is a good thing, than it has to do with the soapstone from my experience. My reasoning behind that is that I can do the same thing with the Defiant and the 30, but I was unable to do that with the Heritage. I found that size of the stove played a bigger difference than what the stove was made out of.

Minister of Fire2.

NULL

I don't think the soapstone would have to be on top of the stove to work. It seems like soapstone floor or maybe soapstone along the lower part of the walls near the stove would gather heat and release it slowly. I am not sure that it would be dramatically better than the brick you already have.

Minister of Fire2.

NULL

There have been some try this and as a young lad we used to have an old soapstone that we'd heat on the wood stove for use in the car or sometimes to warm up the bed. Those were cold times with those old stoves and homes with no insulation.

We know one with a soapstone stove who tried adding another stone to try this and it did not work well at all. Some have tried on steel and cast too but not really good. However, we have small soapstone blocks that we keep on the stove top and use for boot driers and glove driers and even just to keep an extra pair of gloves warm when cutting wood in winter. We also use them under the pots and pans the wife uses for cooking.

On that hedge apple, I hope it is not freshly cut or freshly split. Wood won't dry worth a hoot until it has been split and stacked out in the open air. The most common problem, especially with the epa stoves is poor fuel. The old thing about cutting the winter's wood in the fall is a dead idea. It just don't work.

Click to expand...

I have six slabs that are replacement tops pieces for the Fireview, or slightly bigger. I keep at least two of them stacked on one side of my PH if I am not cooking. They do indeed get very warm...about 50 degrees cooler than the slab under each, so if I have two slabs and the stove top is 400, the slabs would be about 350 and 300. I use them for cooking: this variation in temperature gives me lots of choices for various foods. They add mass and retain and radiate heat as well. And every night they are used as bedwarmers, and radiate heat all night. Wrapped in a beach towel they make the beds toasty and are still warm the following morning. I have twice used them on the hood of my car to start the engine when it is below 30 below out and very windy. I have used them to melt ice that was keeping a door closed. They really are effective as storers and radiators of heat. On days that suddenly drop and are bitterly cold, if we have been outside and feel chilled when we come in, we'll wrap a slab in a towel and put it under our feet, mohair blanket over the legs, and it's very pleasant to sit thus in front of the fire and chat, read, watch a movie, whatever.

The same weight of soapstone will retain twice the BTUs as iron, and radiate them more slowly.

Feeling the Heat2.

NULL

That is more of an indication that your stove is a little over-sized for your needs, which is a good thing, than it has to do with the soapstone from my experience. My reasoning behind that is that I can do the same thing with the Defiant and the 30, but I was unable to do that with the Heritage. I found that size of the stove played a bigger difference than what the stove was made out of.

Click to expand...

Okay, I understand where you are coming from now. I can with agree with that.

Minister of Fire2.

NULL

The same weight of soapstone will retain twice the BTUs as iron, and radiate them more slowly.

Click to expand...

A bit of funny English in your post, such that it could be read in more than one way. "Radiate more slowly," I understand, but please explain how a mass of soapstone charged to the same temperature as an equal mass of cast iron can "retain twice the BTUs as iron."

My area of study is not physics, but is closely related. I prefer to deal with the real physical quantities of energy and power, not the marketing language of a soapstone stove retailer. As I recall, equivalent masses charged to the same temperature will posses equivalent energy. Emissivity dictates how quickly it radiates (power = energy/time), so a lower emissivity mass may at some time during the discharge cycle "retain" twice as much heat as a high emissivity mass, but it's a misleading statement. Both masses radiate the same overall energy back into their environment, and as you already noted, lowering the emissivity of a mass like cast iron can be as simple as wrapping it in a towel.

Minister of Fire2.

NULL

You have to account for the specific heat of the material in question. I've mentioned this a few times before and only received yawns. The specific heat capacity of soapstone has been measured ~2x that of iron/steel. It is basic physics, but I'm not sure exactly how specific heat relates to emissivity.

Minister of Fire2.

NULL

does soapstone retain heat like they say it does? and if so, can you buy a slab or bricks to place on top of a stove to help distribute heat? i've heard good things but wanted to ask first before i jump into anything.

Click to expand...

I believe FirefighterJake ran/runs a slab of soapstone on top of his Oslo, but with spacers.

Minister of Fire2.

NULL

I have six slabs that are replacement tops pieces for the Fireview, or slightly bigger. I keep at least two of them stacked on one side of my PH if I am not cooking. They do indeed get very warm...about 50 degrees cooler than the slab under each, so if I have two slabs and the stove top is 400, the slabs would be about 350 and 300. I use them for cooking: this variation in temperature gives me lots of choices for various foods. They add mass and retain and radiate heat as well. And every night they are used as bedwarmers, and radiate heat all night. Wrapped in a beach towel they make the beds toasty and are still warm the following morning. I have twice used them on the hood of my car to start the engine when it is below 30 below out and very windy. I have used them to melt ice that was keeping a door closed. They really are effective as storers and radiators of heat. On days that suddenly drop and are bitterly cold, if we have been outside and feel chilled when we come in, we'll wrap a slab in a towel and put it under our feet, mohair blanket over the legs, and it's very pleasant to sit thus in front of the fire and chat, read, watch a movie, whatever.

The same weight of soapstone will retain twice the BTUs as iron, and radiate them more slowly.

Click to expand...

And we too have extra stone on our stovetop. We have 2 pair of the boot driers and glove driers. In addition to those, my wife picked up a bunch of the broken stone and she keeps those on top of the stove too.

Minister of Fire2.

NULL

You have to account for the specific heat of the material in question. I've mentioned this a few times before and only received yawns. The specific heat capacity of soapstone has been measured ~2x that of iron/steel. It is basic physics, but I'm not sure exactly how specific heat relates to emissivity.

Click to expand...

True dat. My poor memory failing me again... Energy = mass x specific heat x temp rise. So, soapstone may attain higher energy for a given mass. The remaining question is what this means for a user, in terms of how long it will take to heat up on the front end, and radiate at a given temperature on the back end.